Preparation
1. Whisk together egg whites, water, and the next three ingredients.

2. Heat a small skillet, coated with cooking spray, over medium-high heat for one minute. Pour egg mixture in and cook until the eggs begin to set. Meanwhile, mix the spinach, tomato, and cheese together.

3. Fill half the omelet with the filling, saving some of the cheese, tomatoes, and spinach for a garnish. Work a spatula under part of the omelet and fold it in half. Cook for two minutes, and then slide it onto a plate. Top your omelet with the remaining filling.